What condition is characterized by cramps in muscle groups due to overexertion in hot environments?

Heat cramps are specifically characterized by involuntary muscle contractions or spasms that occur during physical exertion, particularly in hot and humid conditions. This condition typically arises when a person is sweating profusely and loses a significant amount of salt and fluid without sufficient replenishment. The cramps usually affect muscle groups that are actively engaged during exercise, such as the legs or abdomen.

In contrast, hyperthermia is a general term for an abnormally high body temperature, which can encompass various heat-related illnesses but does not specifically refer to muscle cramps. Heat exhaustion is a more severe condition that occurs after prolonged exposure to high temperatures, leading to symptoms like heavy sweating, weakness, and dizziness but typically not muscle cramping as the primary symptom. Heat stroke represents a critical state where the body's temperature regulation fails and is accompanied by a significantly high body temperature, altered mental status, and potential organ dysfunction.

Thus, the key feature of heat cramps, particularly in the context provided, marks it as the correct answer, emphasizing its relation to muscle spasms that arise from overexertion in a hot environment.